A year ago, Snowden provided shocking revelations about the depth and scope of NSA electronic spying on citizens and noncitizens alike. Those revelations split the country between those who saw him as a heroic whistleblower and those who saw him as abetting America's enemies. In an NBC interview, Snowden made a compelling case for his actions.

Those revelations have caused many to rethink how their trust in online services, changed the business climate for U.S. tech companies, and moved the U.S. government to rein in some of the NSA's practices. And only some of the documents Snowden took and gave to journalists have been revealed.

The first revelation from the Snowden files came on June 5, 2013, courtesy of the Guardian newspaper. That initial story revealed how extensively the NSA tracked phone calls, even of U.S. citizens -- contradicting the NSA's earlier statements to Congress that only noncitizens were targeted. Later, it was revealed that the NSA relied on spy agencies such as Britain's GCHQ to spy on Americans on its behalf where the law prevented the NSA from doing so directly.

Snowden-based revelations in late July that the NSA had backdoor access to popular services like Google and Facebook caused the rest of the world to distrust the security of data stored by U.S. Web companies, leading to lost sales.

U.S. providers denied they were cooperating with the NSA, and several tried to release a record of the requests, despite federal gag orders. But they also had to cooperate with any "lawful" requests, which are secret.

Revelations in August showed that the NSA and GCHQ collect much more information on people via Internet spying beyond where they visit and whom they call, including social media and other services.

The initial NSA claims that only metadata on calls -- such as the numbers, dates, and times involved -- were open for question, though the agency continues to deny it monitors the contents of the tracked conversations.

In mid-October, revelations showed that the U.S. spied on 35 world leaders, including allies like German Chancellor Angela Merkel and the E.U. government. The NSA's response: Everyone does that, so what's the big deal? Europeans remain angry and are rethinking cooperation with the United States on several fronts -- and perhaps are turning more attention to spying on us now.

Suddenly, the notion of spies out of control was being taken seriously across political lines. Ironically, countries that have long spied on others, such as China, used the U.S. revelations to deflect concerns about their own notorious efforts.

In late October came news that the NSA created malware to infect computers broadly for spying purposes, essentially using the same methods to infect people's computers as the criminal hacking organizations do.